Purification cassette



FIG. 1 is a top, left and front perspective view of a purification cassette;

FIG. 2 is a front view thereof, the rear view being the same;

FIG. 3 is a left side view thereof, the right side view being the same;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof. 

CLAIM The ornamental design for a purification cassette, as shown and described. 